Help about applying oop on any system or program [Using oop in developing a system/program]

Question

Hi guys,

I just want to know HOW do I start in OOP. I'll explain it further. I am trying to create systems and programs using OOP. But I have a little problem about this. I don't know what classes/objects should I create. Like for example, I will create a reservation system for a hotel. I don't know what objects should I make. Can I use the tables in my database as a reference? Like if I have a "users" table, I should create an object of "users"? I know some basic UML but really can't come up with something because I don't know where to start. Hope anyone could help me cause I've been searching for so long and ended up with nothing but concepts and "an already given objects" examples.

Thanks.